Cross-multiply to see if the ratio forms a proportion. Select Yes if it forms a proportion and No if it does not. (9)/(18)=(1)/(3) No Yes

To determine if the given ratio forms a proportion, we need to cross-multiply and check if the products are equal.<br /><br />Cross-multiplying the given ratio:<br />$\frac{9}{18} = \frac{1}{3}$<br /><br />$9 \times 3 = 18 \times 1$<br /><br />$27 = 18$<br /><br />Since the products are not equal, the given ratio does not form a proportion.<br /><br />Therefore, the answer is No.